Until we started getting customer feedback I thought the site already had this feature, has something changed? We already have an ApplePay disclaimer in our checkout info.
From the first /cart/ page when in the checkout tapping the ApplePay button should immediately give the customer the option to choose their Wallet options and checkout in one step, this happens on all other sites that have ApplePay buttons that I have ever used.
It gives almost no friction at all and would increase conversions, customers choose from which card to use in their wallet, which address and other websites I have used choose which delivery method too.
Tapping ApplePay on our /cart/ immediately goes to the login page, counter intuitive and we get plenty of customer feedback that it's poor, you have to add address etc. Why? the data is all in their wallet.
I get the argument that they can't apply a gift card / voucher code or Reward points if this is the checkout for ApplePay but that's the choice the consumer takes for convenience. Unless of course this can be incorporated in there.
I'd take speed and better conversion by having this immediate "one tap" buying over trying to develop these functions. Our checkout help already says "Unfortunately, Gift Vouchers, Discount Codes, and Rewards points cannot be used with Apple Pay at this time" so why the login step anyway?